Within certain fields for use for industrial robots (manipulators) with several degress of freedom, such as welding, grinding and polishing, there is a need of the manipulator capable of carrying out complex movements.
Certain complex patterns of movement, such as oscillation, have been obtained by superposing signals to control movement in one or two of the coordinate axes of the robot.
However, only a limited number of different oscillating movements are obtained thereby. A generalization of this technique requires the generation of complex control signals, which, besides increasing the complexity of the control system, also increases the demand on the operator. Changes between different types of oscillating movements is furthermore complicated, and accordingly this method has little flexibility.
Another possibility, which may be utilized in robots which can be programmed to move between pre-programmed points, is quite simply to program the entire complex movement by programming in the end points for all the partial movements that the robot is to complete during the complex movement. The complex movement shown in FIG. 3, for example, which is relatively simple, can be defined by programming in all the end points, 13 in number, for the 12 partial movements comprising the complex movement between A and B. This method requires a very high memory capacity because of the normally very large number of points that must be stored, and for the same reason programming or reprogramming, for example, an alteration of the principal movement AB, becomes very time-consuming.